I like your old med Calc better. This one needs the BMI calculator to include by gender. And I would suggest to see if you can add the recommendations for weight gain in pregnancy by BMI by the Institute of Medicine.
Also have a table with recommended wt for women by height. It also categorizes underweight, normal weight, overweight, and obesity by BMI ranges. It would be great to get this onto MedCalc.
I use this table to quickly use pre-pregnancy weight and obesity category to go to the Institute of Medicine table to make recommend weight gain in pregnancy.